Kinetic studies will be conducted with UDPGlc dehydrogenase from bovine liver. Such studies will include steady-state studies at varying concentrations of substrate and cosubstrate, with special emphasis on the effect of the feedback inhibitor UDPXyl. In addition, stop flow studies will be carried out with substrates and substrate analogues. UDPGlc dehydrogenase from Escherichia coli will be further purified, if possible, to homogeneity. Physical, chemical, and catalytic properties of the enzyme will be investigated, especially in comparison to those of the UDPGlc dehydrogenase of bovine liver.